Thin layer chromatography of 28 aromatic amines has been performed on silica gel layers using organic solvents of different polarities as mobile phases. The mobility of amines generally depends upon the polarity of the mobile phase used. The analytically difficult separations of p-dimethylaminobenzaldehyde (p-DAB) from P-dimethyaminocinnamaldehyde (p-DAC) has been achievd on silica layers after their derivatization with diphenylamine on TLC plate.